To sum up the difference on this day compared to any other day, they put out portapotties and I counted 2 performance stages. They look like they are expecting a larger than usual crowd for New Years. The Enterprise library, further down the strip closes an hour earlier than usual. Maybe it might be worth checking out the activities.
I would expect the people who can afford to sleep in the hotels downtown to be more likely out around the city. Although, there are quite a few homeless people who find corners to sleep in. I probably passed about 30 homeless people at various parts of the strip.